Not a bad fusion build here. I think your ratios on the core BEWD engine--at least the monsters--is pretty much spot-on (I'd run 2x Stone of Ancients, 1x Stone of Legend but w/e). Friendly suggestion on main deck monsters would be to sub out the second Nebula Dragon for Chaos Dragon Levianeer. I appreciate the defensive potential here, but you really don't need to run 2x Effect Veiler if you're also running 2x Ash--one of each to main deck is probably more than enough (in fact, I might give the edge to Veiler and run it at 2x because of the synergy with Sage).
On spells, I think you need to run more of the core engine. 3x Melody, 3x Return of the Dragon Lords, 3x Trade-In, and--if you're serious about the fusion build--at least 2x Poly (probably reckless to run less than 3x but you're already over the 40-mark).